In an effort to open up overly congested airways and deliver high quality television images, several countries are currently exploring converting from an analog signal infrastructure to a digital signal infrastructure. Converting to digital signals frees up bandwidth so that all devices, such as cellular phones and police and air traffic control systems, can operate more safely and efficiently. In addition, converting to digital signals allows television broadcasters to deliver a signal that generates a picture quality that can be up to 94% of the resolution of 35 mm print film. The quality of this picture is so amazing that many video and film engineers cannot even distinguish it from a picture generated from an actual 35 mm print.
The United States is among the countries exploring digital signal infrastructure. In particular, the United States Congress has mandated that most television broadcasters convert from analog signals using the National Television Standards Committee (NTSC) standard to digital signals using the Advanced Television Systems Committee (ATSC) standard (conventionally known as the High Definition Television (HDTV) standard) by 2006. As part of that mandate, on Aug. 8, 2002 the United States Federal Communications Commission voted to require television manufacturers to add digital tuners to all television sets with screens of 36 inches and larger by July 2005, while the requirement for smaller sets would be phased in over the following two years. (MM Docket No. 00-39, Adopted Aug. 8, 2002).
Unfortunately, television broadcasters have been slow to fulfill the potential of this new digital format. Though some new television programs are being recorded in HDTV, there is not enough digital subject matter to meet viewer demand. To alleviate this problem, a number of broadcasters have attempted to convert older television shows to the HDTV standard and have found that the cost for post-production facilities to perform the conversions using standard editing methods is simply too high.
Most television shows are shot on 16 mm or 35 mm film. Prior to the late 1990s, depending on budgets at the time, studios edited shows for broadcast using one of two methods. Both methods create a high-end NTSC videocassette, an edited master, of the assembled show for NTSC broadcast. The first method, known as the negative cutting process, required that an editor identify the final negative segments, cut out final negative segments from the original negatives, and bind those cut negative segments into an assembly reel. This assembly would then be printed as one piece of film, a composite, in a film lab before being transferred to NTSC video, through the telecine process, for broadcast. This was one of the most commonly used high quality methods available in the early 1980s.
With the rise of video editing and the birth of digital video editing, a generally less expensive second method, known as on-line editing, became possible. This method required that all the original negative segments be transferred to NTSC video and assembled in an electronic editing bay for broadcast. To better understand the on-line editing, FIG. 9 illustrates the prior art method of an NTSC program assembly using on-line editing. As discussed above, many television programs use 35 mm film as the original recordation media. The size of the film (i.e., 35 mm) is known as the gauge of the film. This film has several frames, with each frame having a unique number associated with it. This number is known as a keycode. For example, in 35 mm the film stock manufacturer imprints a unique imprinted keycode every 64 perforations. The distance between imprinted keycodes is known as a keyfoot. Cameras generally record images on the 35 mm film at one frame per four perforations. Accordingly, 35 mm film has 64 perforations per keyfoot (PPK) and 16 frames per keyfoot (FPK). Knowing the unique imprinted keycode immediately before the relevant frame, plus the offset of frames from that keycode will give you the unique keycode for that frame. As with 35 mm, other film gauges have unique keycodes based on a similar offset method. For example, 16 mm has 20 or 40 PPK and either 20 or 40 FPK; and 70 mm has 120 PPK with either 24 or 8 FPK.
The original film rolls 1-3 are fed into a NTSC telecine bay 4 that transfers the film images into NTSC source tapes 5-7. While FIG. 9 illustrates N-number of original film rolls and K-number of NTSC source tapes, it is possible that only one original film roll and/or only one NTSC source tape be used in the assembly of the NTSC program. At the NTSC telecine bay 4 a telecine operator makes telecine decisions 8 regarding which possible segments may be needed in the development of the final video program. For example, a director may shoot several different segments at multiple angles for any given scene. The director may then direct the telecine operator to transfer all those segments at the various angles so that the director may view each alternative and select the appropriate one at the off-line editing bay 9 described below.
The NTSC telecine bay 4 keeps track of each of the telecine decisions 8 in the form of a NTSC telecine log (NTSC-TL) 10. This log 10 is often called a Flex File. Other common proprietary formats for the log 10 include Key Log, Evertz, Avid Log Exchange, Aaton, Key Scope and Log Producer. Notwithstanding the proprietary format, the log 10 usually has several entries, with each entry containing general information that may include the following:                (a) film roll number (i.e., 1, 2 or 3) describing the actual film roll from which the entry's segment was taken;        (b) source tape number (i.e., 5, 6, or 7) describing the NTSC source tape to which the entry's segment was transferred;        (c) scene number describing the scene number for the entry's segment;        (d) take number describing the scene take number for the entry's segment;        (e) flash timecode IN describing the timecode in HH:MM:SS:FF (Hours:Minutes:Seconds:Frames) format for the source tape start position for the entry's segment;        (f) flash timecode OUT describing the timecode in HH:MM:SS:FF format for the source tape end position for the entry's segment;        (g) flash keycode IN describing the unique keycode for the start film frame for the entry's segment;        (h) flash keycode OUT describing the unique keycode for the end film frame for the entry's segment;        (i) gauge of the film describing the size of the film; and        (j) other miscellaneous information such as sound timecodes, project title, production company, the name of the telecine operator, the machines used in telecine, date of the telecine transfer, and date when the segment was taken.        
After the telecine operator transfers the original film rolls 1-3 to NTSC source tapes 5-7, those source tapes are fed into an off-line editing bay 9 where an editor makes edit decisions 11 regarding which segments should be included in the edited NTSC master 12. In addition to selecting the appropriate segments, the editor must order those segments. As with the telecine decisions 8, the director may play a significant role in selecting the final segments and their appropriate ordering. Others may also play a role in final segment selection including content providers, producers, editors and visual effects supervisors. All of the edit decisions 11 at the off-line editing bay 9 are recorded in an NTSC edit decision list (NTSC-EDL) 13. This list 13 usually has several entries, with each entry containing general information that may include the following:                (a) project title;        (b) assembly number describing the relative ordering of the entry's segment;        (c) source tape number describing the NTSC source tape (i.e., 5, 6, or 7) where the entry's segment is located;        (d) source timecode IN describing the timecode in HH:MM:SS:FF format for the start location on the source tape for the entry's segment;        (e) source timecode OUT describing the timecode in HH:MM:SS:FF format for the end location on the source tape for the entry's segment.        (f) destination timecode IN describing the timecode in HH:MM:SS:FF format for the start location on the destination tape for the entry's segment;        (g) destination timecode OUT describing the timecode in HH:MM:SS:FF format for the stop location on the destination tape for the entry's segment; and        (h) scene and clip name for the entry's segment.        
The NTSC-EDL 13 is then fed into an on-line editing bay 14 that automatically assembles the edited NTSC master 12, by transferring the appropriate video footage described in the NTSC-EDL 13 from the NTSC source tapes (5, 6, or 7).
FIGS. 10 and 111 illustrate the transfer of segments from the original film rolls 1-3 to the edited NTSC master 12 just described. In FIG. 10 the original film rolls 1-3 are represented as a line of footage with potentially relevant segments shown as gray blocks. The gaps between the gray blocks represent non-usable footage. For example, before a slate marks the scene and the relevant footage begins, directors or camera operators often let the cameras run while the cast and crew come into position. The telecine operator makes telecine decisions 8, shown as arrows 14, as to which segments may be used in the edited NTSC master 12. Here in FIG. 10, the telecine decisions 8 rejected one segment from film roll 1 and two segments from film roll 3, and transferred the remaining segments to NTSC source tapes 5 and 6. Then the editor must make editing decisions 11, shown as arrows 15, as to which segments will be used in the edited NTSC master 12, and the ordering of those segments. In this example, two segments from NTSC source tape 5 and two segments from source tape 6 did not make the final cut, and relevant segments from the two source tapes 5 and 6 are reordered in the edited NTSC master 12.
FIG. 11 is similar to FIG. 10, but illustrates a complete telecine of all original film rolls 1-3 to NTSC source tapes 5-7. In other words, the telecine decisions 8, illustrated as arrows 14, direct that the entire film roll, along with the non-usable gaps, be telecined to the NTSC source tapes 5-7, without rejecting any film footage. Then the editor makes the editing decisions 11, shown as arrows 15, as to which segments will be used in the edited NTSC master 12, and the ordering of those segments.
A director may prefer the alternative illustrated in FIG. 11 over that of FIG. 10 because it allows her to review all the footage and make the edit decisions 11 with all the possible footage alternatives before her. The alternative of FIG. 11, however, is generally more expensive than that of FIG. 10 because the telecine process is very expensive and is dependent on the amount of footage actually telecined. Thus, it is generally less expensive to know which scenes may be used in the edited NTSC master 12, and direct the telecine operator to telecine only those scenes. Oftentimes the director and editor do not know beforehand which segments will ultimately be used, but have a general idea as to which segments would make good candidates for the edited NTSC master 12. Ultimately the process described with reference to FIG. 9 yields an NTSC-TL 10, an NTSC-EDL 13 and an edited NTSC master 12.
In order for these television shows now to be upgraded from NTSC video to higher picture quality of HDTV, it is necessary to use a source with image clarity, or resolution, that is the same as or higher than HDTV. Film negatives, composite prints, and their intermediaries have greater resolution than a HDTV video signal; therefore, for those shows that underwent the negative cutting process, one simply transfers the already assembled film to high definition in a HDTV telecine bay. The resulting cassettes are used for HDTV without noticeable quality loss.
For shows that underwent the on-line editing process described with reference to FIG. 9, several problems exist when converting the NTSC-assembled program to HDTV. First, one simply cannot convert the edited NTSC master 12 to HDTV, nor can one use the NTSC source tapes 5-7 for HDTV conversion because NTSC video quality is substantially lower than HDTV. Second, the edited NTSC master 12 and the NTSC source tapes 5-7 are based on 30 frames per second (FPS), while HDTV is based on 24 FPS—thus, the existing NTSC-TL 10 and NTSC-EDL 13 cannot be used in the HDTV realm. Third, the existing NTSC-TL 10 contains not only the segments used in edited NTSC master 12, but also includes segments that the editor ultimately rejected (see e.g. FIG. 10, NTSC source tape 5 has two rejected segments). Therefore, the NTSC-TL 10 may be over inclusive, requiring very expensive telecine time.
Against the backdrop of these problems, only two options are available for converting the online edited NTSC program to HDTV, however both are risky, costly and time consuming. The first option is to undergo the negative cutting process described above. This requires the labor of a film conformist, a negative cutter, and other editorial aides and equipment to completely reassemble the show. After the negatives are assembled, the assembly is then telecined to HDTV. Unfortunately, every time film technicians handle a film negative, they risk damaging the negative with dirt, hair, scratches or worse. Further, negative cutting is a very precise and rather risky process that when not performed correctly can cause irreparable damage to the original film stock. Cutting negative also eliminates the ability to re-cut a show or use the film stock for future projects.
The second option is to telecine all the negatives to HDTV and then conform the show through HD on-line editing using high-end HDTV editing bays. Because negatives are not cut, this process avoids the risk of causing damage to the original film. However, because a professional editor must spend a significant amount of time sorting through the show's many segments to find each used segment of the show, this process is rather expensive and is still subject to human error. Also, telecining all the negatives to HDTV is very expensive, further driving up the costs.
Therefore, a need exists for a conversion method that increases the efficiency, speed and accuracy of the HD on-line editing process, reducing labor costs and freeing up valuable edit bay time.